Control for an electric circuit breaker with valve and piston operating means

ABSTRACT

A control for the control-valve mechanism of an electric circuit breaker comprises means biasing the operating piston of said mechanism in a direction to effect circuit-breaker closing. Releasable latch means restrains the operating piston in a circuit-breaker-open position against this bias. A closingcontrol operator for the latch means is operable to release the latch means, thereby allowing the operating piston to be moved in a circuit-breaker-closing direction. An opening-control operator is effective when operated to develop an opening-control force for use in driving the operating piston through opening-control motion. Force-transmitting means effective when the latch means is reset serves to transmit said opening-control force from said opening-control operator to said operating piston. Latchresetting means effectively resets the latch means following and in response to release of the latch means.

United States Patent [1 1 Barkan et al.

[ CONTROL FOR AN ELECTRIC CIRCUIT BREAKER WITH VALVE AND PISTON OPERATING MEANS [75] Inventors: Philip Barkan, Media; John A.

Oppel, Aldan, both of Pa.

[73] Assignee: General Electric Company,

Philadelphia, Pa.

[22] Filed: Oct. 19, 1973 [21] Appl. No.: 408,013

[52] US. Cl. 200/82 B; 200/148 F; 137/529 [51] Int. Cl. H0lh 35/38 [58] Field of Search 335/174, 191; 200/82 R,

ZOO/82 B, 82 C. 169 R, 145, 153 G, 153 V, 153 H, I48 E, 148 F; 137/493], 528, 529, 530

[56] References Cited UNITED STATES PATENTS 2,667,554 1/1954 Shores ZOO/148 F 2,783,338 2/l957 Beatty ZOO/I48 F 3,334,202 8/l967 Tognella..... ZOO/82 B 3,566,054 2/l97l Barkan ZOO/I48 B 3,646,292 2/1972 Porter ZOO/82 B [4 1 May 20, 1975 Primary Examiner-Robert K. Schaefer Assistant ExaminerGerald P. Tolin Attorney, Agent, or Firm-J. Wesley Haubner; William Freedman [5 7] ABSTRACT A control for the control-valve mechanism of an electric circuit breaker comprises means biasing the operating piston of said mechanism in a direction to effect circuit-breaker closing. Releasable latch means restrains the operating piston in a circuit-breaker-open position against this bias. A closing-control operator for the latch means is operable to release the latch means, thereby allowing the operating piston to be moved in a circuit-breaker-closing direction. An opening-control operator is effective when operated to develop an opening-control force for use in driving the operating piston through opening-control motion, Forcetransmitting means effective when the latch means is reset serves to transmit said openingcontrol force from said opening-control operator to said operating piston. Latch-resetting means effectively resets the latch means following and in response to release of the latch means.

10 Claims, 5 Drawing Figures PATENTEBHAYZUHH 338M113 SHEET 2 BF 4 OPEN/N6 CLOS/NG PMENTED imam 3,885.1 13

SHEET 3 BF 4 PATENTEDHAYZOISYS 3,885,113

sum u 0F 4 CED (ID (C/RCU/T fi/PEA/(ER 040650,- TOGGLE JUBSTA/VT/ALLY R5657) 1 CONTROL FOR AN ELECTRIC CIRCUIT BREAKER WITH VALVE AND PISTON OPERATING MEANS BAC KGROU N D This invention relates to a control for an electric circuit breaker and, more particularly, to a control that is capable of effecting an exceptionally fast response by the circuit breaker to a closing command as well as to an opening command, even though these commands may be initiatedin rapid succession.

In certain circuit applications, a high voltage circuit breaker is required to operate from a normally open position to a closed position within an exceptionally short time, e.g., 25 milliseconds. This is in marked contrast to the closing time of conventional high voltage circuit breakers, one typical form of which requires about 170 milliseconds to close following initiation of a closing command. To meet this 25 millisecond requirement, it is required that the usual control valve of the circuit breaker be shifted between its closed and open positions within a few milliseconds, as compared to the 50 or 60 milliseconds now typically needed.

Another requirement of such a circuit breaker control is that it be capable of initiating a circuit-breakeropening operation as soon as the circuit breaker reaches its closed position, which in the above-noted application is only 25 milliseconds after the closing command is supplied. Still another requirement is that the control be capable of initiating a circuit-breaker reclosing operation immediately following an opening operation.

SUMMARY Thus, an object of our invention is to provide a circuit breaker control which is capable of effecting an exceptionally fast response by the control valve of the circuit breaker to both a closing command and an opening command, even though these commands may be initiated with only a short interval therebetween.

In the control that we are concerned with, there is a control valve member at high potential, an operating piston therefor at ground potential, and a long insulating rod interconnecting the control valve member and the piston. The length of the rod may vary slightly from time-to-time as a result of temperature and pressure changes. The control valve member is maintained in a position that is unchanged by these variations in rod length, thus preventing any unintended circuit breaker operation from resulting therefrom, but, however, causing the position of the operating piston to shift slightly as a result of these variations in the rod length.

Another object of our invention is to provide a control for the operating piston which: (1) allows such shifts in the position of the piston and (2) has a performance that is substantially unaffected by such shifts in piston position.

In carrying out our invention in one form, we provide: l means for biasing the above-described operating piston of the control-valve mechanism in a direction to effect a circuit-breaker-closing operation of the movable control-valve member and (2) latch means for restraining the operating piston in a circuit-breakeropen position against said bias. We also provide a closing-control operator for the latch means that is operable to release the latch means and thus render it incapable of continuing to restrain the operating piston in its circuit-breaker-open position, thereby allowing the biasing means to operate the piston in a circuit-breakerclosing direction. An opening-control operator is effective when operated to develop an opening-control force for use in driving the operating piston through circuit-breaker-opening control motion. Means effective when the latch means is reset is provided for transmitting said opening-control force from the openingcontrol operator to said operating piston. Latchresetting means is provided for effectively resetting said latch means following and in response to a release of the latch means.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic showing of a high voltage circuit breaker embodying one form of our invention. The circuit breaker is shown in its open position.

FIG. 2 shows a portion of the circuit breaker of FIG. 1 in the circuit-breaker-closed position.

FIG. 3 is an enlarged view of a control portion of the circuit breaker of FIG. 1, showing the parts in the circuit-breaker-open position.

FIG. 4 is a view similar to FIG. 3 except showing the parts of the control immediately after the control has been operated from its position of FIG. 3 to command the circuit breaker to close. The control is depicted before being reset.

FIG. 5 shows the parts of FIG. 4 in the circuitbreaker-closed position but after having been reset.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT The Circuit Breaker and Its Control Valve Mechanism Referring now to the schematic illustration of FIG. 1, there is shown an electric circuit breaker that comprises a metal tank 10 at high potential and a hollow insulating column 12 atop which the tank is mounted. Within tank 10 are two pairs of separable contacts 14, 15 and 16, 17 electrically connected in series. For actuating the movable contacts 15 and 17 of the two pairs, an operating mechanism 20 is provided. Suitable mechanical links 22 couple the movable contacts 15 and 17 to the operating mechanism. The stationary contact of each contact pair is carried by a conductive stud 25 which forms a part of a conventional lead-in bushing comprising a porcelain shell 26.

The parts within tank 10 can be of a suitable conventional design and are therefore shown in schematic form only. The operating mechanism 20 can be of the type disclosed, for example, in U.S. Pat. No. 2,783,338- Beatty, assigned to the assignee of the present invention. When the operating mechanism 20 operates during a closing operation, it drives movable contacts 15 and 17 into closed position substantially simultaneously. During an opening operation, operating mechanism 20 drives contacts 15 and 17 into their open position substantially simultaneously.

Tank 10 contains a high pressure gas, and this is used for operating the mechanism 20. For controlling mechanism 20, a control valve 30, shown in simplified schematic form in FIGS. 1 and 2, is provided in a control conduit 32 interconnecting the pressurized interior of tank 10 and operating mechanism 20. This control valve 30 comprises a movable valve element 34 that is vertically movable between two positions, one of which is shown in FIG. 1 and the other in FIG. 2. When in the position of FIG. 1, the valve element 34 permits communication between the interior of tank and conduit 32 via an inlet port 33 in the valve housing 36. In the position of FIG. I, the movable valve element 34 also abuts against a seat 37 at the upper end of the valve housing and thus prevents pressurized fluid from flow ing into a vent passage 38 from either the tank 10 or operating mechanism 20. When movable valve element 34 is shifted downwardly into its position of FIG. 2, it abuts against a seat 39 and thus blocks communication between the interior of tank 10 and operating mechanism 20. When valve element 34 is in this position of FIG. 2, a vent port 41 affords communication between the vent passage 38 and control conduit 32, thus venting operating mechanism 20.

When control valve 30 is in its open position of FIGv 1, operating mechanism 20 is under pressure and thus holds the contacts open in the manner shown in the aforesaid Beatty patent. When control valve 30 is operated to its position of FIG. 2, operating mechanism 20 is vented. and suitable biasing means within the operating mechanism operates the movable contacts and 17 to their closed position in the manner disclosed in the aforesaid Beatty patent.

For operating the movable valve member 34, there is provided at the lower end of insulating column 12 an operating piston 40 which is mechanically connected to the movable valve member 34 by means ofa long insulating rod 42. When the operating piston 40 is driven downwardly from its position of FIG. 1, it shifts the movable valve member 34 downwardly to effect circuit-breaker closing. Return movement of operating piston 40 to its position of FIG. 1 results in returning valve member 34 to its position of FIG. 1, thereby opening the circuit breaker.

The Control for the Control Valve Mechanism For controlling the operating piston 40, there is provided a control 45 shown in block form in FIG. 1 but in more detail in FIGS. 3-5. Referring to FIG. 3, control 45 comprises an opening-control motor 50 comprising a cylinder 51 and a piston 52 reciprocable therein. Opening-control piston 52 is mechanically connected to the operating piston 40 through a beam or link 55. At one end, beam 55 is coupled to the opening-control piston 52 through a pivot pin 57 and a push rod 57a and at its other end is coupled to the operating piston 40 through a pivot pin 59 and a push rod 59a. Intermediate the pivotal connections 57 and 59, the beam 55 has another pivot 60. This pivot 60 is normally held in its reset position of FIG. 3 by suitable latch means 62 soon to be described.

The cylinder space above the operating piston 40 is always filled with gas at a high pressure corresponding to that in the tank 10. As shown in FIG. 1, communication between the tank space and the cylinder space is afforded through an insulating pipe 43 extending through column 12. The space beneath piston 40 is at atmospheric pressure. Thus, there is always a biasing force acting in a downward direction on operating piston 40.

The cylinder space 63 above the opening-control piston 52 is normally filled with gas at the same high pressure as in the tank 10, but this space 63 can be vented to atmosphere to allow piston 52 to move upward under certain conditions soon to be described. Beneath the opening-control piston 52 within cylinder 51 there is a buffer 65 that forms a stop for limiting downward motion of piston 52. Normally, the piston 52 is spaced a short distance above the buffer 65.

The pressure in cylinder space 63 is controlled by an opening-control valve 67 connected in a line 66 leading to cylinder space 63. This valve 67 comprises a reciprocable valve member 68 that occupies the position illustrated in FIG. 3 when the circuit breaker is open. In its position of FIG. 3, valve member 68 bears against a seat 69 near its right-hand end, thus sealing offline 66 from a vent 70 leading to atmosphere. When in the position of FIG. 3, valve member 68 allows for free communication between a high pressure port 72 and the line 66, thus connecting cylinder space 63 with the same high pressure source as used for supplying tank 10. The movable valve member 68 includes two pistons 73 and 73a, each having a right hand surface on which high pressure gas acts to provide a net force on the valve member from the pressurized gas biasing the valve member toward the left. However, when the parts of the control 45 are in their position of FIG. 3, valve member 68 is prevented from moving to the left by the latch means 62 against which its left hand end 85 bears.

The latch means 62 is constituted by a toggle linkage comprising links 75 and 76 pivotally connected together by a knee 77. The lower toggle link 76 is pivotally mounted on a stationary pivot 80, and the upper toggle link 75 is pivotally mounted on the pivot 60 on beam 55. As shown in FIG. 3, the normal position of the toggle 75, 76 is slightly to the right of center with respect to a reference line 81 connecting the center lines of pivots 80 and 60. A torsion spring 95 biases the knee 77 of the toggle toward the right and into its position of FIG. 3.

When the parts are as shown in FIG. 3, the knee 77 of the toggle 75, 76 is blocked from moving further overcenter (ie, to the right of reference line 81) by the valve member 68 and an actuating lever 84 that has a portion located between knee 77 and a projecting end 85 of the valve member 68. This actuating lever 84 (the purpose of which will soon be described) is pivotally mounted on stationary pivot 80 and bears at its upper end against a projecting end 85 of the valve member 68. Referring still to FIG. 3, since valve member 68, 85 is bearing against seat 69 at its right hand end, it is able to cooperate with lever 84 to block further overcenter movement of toggle 75, 76.

A Closing-Control Operation For actuating the toggle 75, 76, a conventional closing control solenoid 87 is provided. This solenoid comprises a movable armature (not shown) that is pivotally connected to toggle link 76 through a horizontally extending operating rod 88. When closing-control solenoid 87 is energized, it drives operating rod 88 to the right, pivoting toggle link 76 in a counterclockwise direction about pivot 80, thereby driving toggle 75, 76 toward and then past its center line 81. When this occurs, the toggle 75, 76 is no longer able to restrain the beam 55 from moving downwardly under the influence of the downward biasing force above operating piston 40. Accordingly, this downward force on piston 40 drives the piston 40 and connecting rod 42 downwardly, thereby shifting the main control valve member 34 downwardly to produce circuit-breaker closing.

The above-described downward movement of the operating piston 40 also causes the beam 55 to move downwardly, collapsing the toggle into its position of FIG. 4. The pressure then present above the openingcontrol piston 52 causes piston 52 also to move downwardly, but this motion is terminated by buffer 65 after only a short travel. Upon this termination of downward movement of opening-control piston 52, the downwardly moving beam 55 pivots counterclockwise about the pivot 57 that connects the beam to the openingcontrol piston, finally reaching the position illustrated in FIG. 4, where motion of the toggle 75, 76 and the beam 55 is terminated by a suitable stop 89.

The buffer 65 that engages opening-control piston 52 during the above-described closing-control motion serves to reduce the extent which the toggle 75, 76 must travel in order to allow a full stroke of operating piston 40 as compared to the toggle travel that would be needed if downward travel of the opening-control piston 52 was allowed to continue. In addition, by dissipating the kinetic energy of the piston 52, the buffer 65 relieves the toggle stop 89 from the need to dissipate this energy, thus reducing the duty on this stop 89 and reducing the likelihood of bounce at the end of the toggle travel.

To assure that the upper control valve member 34 (FIGS. 1 and 2) fully seats in its position of FIG. 2 at the end of the closing-control operation, the push rod 590 is made free to separate from the operating piston 40 and is not positively connected thereto, as will be apparent from the clearance space 105 shown in FIG. 4. This separable connection also serves to allow the toggle 75, 76 to move into its position of FIG. 4 without undue impedance from the operating piston 40.

Resetting the Toggle After the operating piston 40 has been moved downwardly, as above-described, to initiate a circuitbreaker-closing operation, the control 45 must be quickly prepared for any circuit-breaker-opening operation which might be required when the circuit breaker reaches closed position. As part of this preparation, the movable valve member 68 of opening-control valve 67, which is naturally biased to the left as above described, shifts in response to the above-described latch-release from its position of FIG. 3 into its position of FIG. 4, thus venting the space 63 above opening-control piston 52. When the space 63 is thus vented and the pressure therein drops to a predetermined level, the torsion spring 95 on the toggle-type latch 62 is free to reset the toggle latch 75, 76 from its position of FIG. 4 to that of FIG. 5. A light compression spring 96 beneath the opening-control piston 52 also aids in this resetting action.

More specifically, this resetting of the toggle latch is effected as follows. When the space 63 above openingcontrol piston 52 is vented, the torsion spring 95 and the compression spring 96 restore the toggle to a position slightly overcenter as shown in FIG. 5. During the initial part of this toggle-resetting, the left-hand end of beam 55 moves upward a short distance to take up the clearance 105 but is not able to move upwardly further in response to additional toggle-resetting in view of the pressure above operating piston 40. But the right-hand end of beam 55 is free to move upwardly in response to this toggle-resetting since the space 63 above piston 52 has been vented.

Resetting of the toggle 75, 76 progresses to the point depicted in FIG. 5 but is then blocked by the valve member 68, from progressing further. The natural bias to the left on the movable valve member 68 is sufficiently strong to prevent the valve member from being displaced by the resetting action of the toggle. This resetting of the toggle 75, 76 can be completed in a substantially shorter time than the time required for the circuit breaker to complete its closing operation (e.g., about 22 milliseconds following operation of the main control valve 30 in the assumed high speed closing application). When such toggle-resetting occurs, the control is ready to initiate a circuit-breaker opening operation when called upon to do so. It will be understood that unless the toggle 75, 76 is reset into substantially its position of FIG. 5, the force-transmitting link 55 is ineffective to transmit any opening-control force developed by motor 50 to the operating piston 40.

An Opening-Control Operation For effecting circuit-breaker-opening control motion of operating piston 40, an opening-control solenoid is provided. The usual movable armature (not shown) of the solenoid 100 is connected through a horizontally-extending operating rod 102 to the actuating lever 84. When the solenoid 100 is energized, it drives operating rod 102 to the left from its position of FIG. 5, pivoting actuating lever 84 clockwise about stationary pivot 80. This causes the upper end of actuating lever 84 to drive movable valve member 68 a short distance to the right from its position of FIG. 5 into its position of FIG. 3. Such movement of valve member 68 allows pressurized gas from port 72 to flow past valve member 68 and via line 66 into the cylinder space 63 above opening-control piston 52. Opening-control piston 52 responds by moving downwardly to drive beam 55 clockwise about pivot 60, thereby applying an upward force on the operating piston 40. This force, combined with the force resulting from pressurized gas in the tank 10 acting on the bottom of main control valve member 34, acts to rapidly drive the main control valve member 34 upwardly from its circuit-breaker-closed position of FIG. 2 to its circuit-breaker-open position of FIG. 1, thus effecting circuit-breaker opening.

The movement to the right of opening-control valve member 68 described in the immediately-preceding paragraph resulted in a slight amount of followup movement to the right by the knee 77 of the toggle 75, 76, but substantially no movement of the pivot 60 on beam 55 since the toggle was near its dead center position. The toggle is therefore considered to have been essentially completely reset in its position of FIG. 5, and the slight shifting thereof occurring between FIGS. 5 and 3 does not materially affect the toggle.

Reclosing and Reopening Operations If it is desired to rapidly reclose the circuit breaker following this opening operation, such reclosing can be effected simply by energizing the closing solenoid 87 to release the toggle latch 75, 76. This allows biasing force above piston 40 to immediately drive piston 40 downwardly (to effect circuit-breaker closing) despite any residual pressure remaining in the space 63 above opening-control piston 52. Such downward movement of operating piston 40 simply pivots the beam 55 about pivot 57. The parts then operate in the same way as during the normal closing operation described hereinabove.

The control 45 is capable of indefinitely repeating opening and closing operations whenever commanded to do so even though there are only very short intervals between the opening and closing commands (assuming, of course, that the breaker is open when the closing command is received and closed when the opening command is received). Normally, however, the breaker can tolerate only a predetermined number of such closely successive operations, and suitable means (not shown) provides for lockout before this limit is reached.

GENERAL DISCUSSION One feature of our control 45 contributing to its fast response to a circuit-breaker-closing command is that there is no need in our control to dump any pressurized fluid chamber and wait for the pressure therein to decay before motion of the main control valve member 34 can be initiated. Although the pressure in chamber 63 above the opening-control piston 52 normally acts in a direction to oppose downward circuit-breakerclosing motion of piston 40 from its position of FIG. 3, such opposition is rendered ineffective by tripping of the toggle latch 75, 76 which allows the beam 55 to move downwardly without opposition from the pressure in chamber 63. As a matter of fact, this pressure in chamber 63 aids initial downward movement of beam 55 and operating piston 40.

It will be noted that the closing-control solenoid 87 acts directly on the latching toggle 75, 76, and this also helps to obviate the need for any pneumatic operations as a condition precedent to initiating downward motion of the operating piston 40.

While the toggle latch 75, 76 must be reset from its position of FIG. 4 before an opening-control operation of the operating piston 40 can be initiated by the opening-control motor 50, this resetting introduces no significant delay in initiating circuit-breaker opening inasmuch as this resetting occurs during the period while the circuit breaker is in the act of closing following operation of the main control valve 30 into its position of FIG. 2. Such resetting is readily accomplished within this period (which would be about milliseconds even in this very high speed closing application).

As pointed out in the introductory portion of this specification, the long insulated operating rod 42 must be free to expand and contract without initiating operation of the circuit breaker, which means that the operating piston 40 at its lower end must be free to shift slightly without interference from the control 45. In addition, the operation of the control should not be affected by such shifting of the piston 40. It will be apparent that when the circuit breaker is open, as depicted in FIG. 3, our control permits such shifting of the piston 40 to occur freely since such shifting simply causes pivoting of the beam 55 about the latched pivot 60, resulting in vertical movement of the opening-control piston 52. The opening-control piston 52 is able to move freely upward since such movement simply displaces pressurized gas thereabove through the supply line 66 past the open valve 68 and out the port 72 into the high pressure source. No pressure buildup results from such piston movement since the valve member 68 is in its open position. Appropriate downward movement of the opening-control piston 52 is also possible since there is a clearance space between piston 52 and buffer 65. Such downward motion of piston 52 could occur,

for example, in response to contraction of elongated rod 42.

Even though the beam 55 pivots slightly in response to such shifting of operating piston 40, the beam is still free upon latch-release to move downwardly in the same way as described hereinabove to allow for circuitbreaker closing. Such pivoting of beam 55 does not affect the toggle latch 75, 76, or its actuators, or the opening-control valve 67.

When the circuit breaker is in its closed condition, as shown in FIG. 5, shifting of the piston 40 to accommodate minor changes in the length of rod 42 can readily be accommodated since such shifting simply pivots the beam 55 about the pivot 60, slightly shifting the opening-control piston 52 as appropriate. Since in FIG. 5 the space 63 above piston 52 is vented, such shifting of piston 52 can occur freely.

Another advantage of our control is that it has no need for continuous energization of either the openingor the closing-control solenoids and 87 and also no need for holding magnets or the like to hold either of the solenoid armatures in its operated position. The only duty that the closing-control solenoid 87 has imposed upon it is to drive the toggle 75, 76 from its position of FIG. 3 to an unlatched position slightly past dead-center. When this triggering action has been accomplished, the closing-control solenoid may be, and is, deenergized (by suitable switch means, not shown); and the closing operation can continue to completion without further assistance from the closing-control solenoid. The only duty that the opening-control solenoid 100 has imposed upon it is to drive the movable opening-control valve member 68 through the short distance from its position of FIG. 5 to that of FIG. 3, where valve member 68 is held by the torsion spring 95. Once the opening control valve reaches its position of FIG. 3 in response to this triggering action by the opening-control solenoid 100, the circuit-breaker opening operation can continue to completion without further assistance from the opening-control solenoid 100. Accordingly, the opening-control solenoid 100 is deenergized (by suitable switch means, not shown) as soon as it shifts the valve member 68 into its position of FIG. 3 from that of FIG. 5.

Since each of the solenoids 87 and 100 is not needed, and is therefore deenergized, after its initial triggering operation above described, it will be apparent that there is no need for either solenoid to work against the other or for either to be continuously energized. Since the armature, when deenergized, may return to its normal position, there is no need for any holding magnet or the like for holding the armature in its operated position.

While we have shown and described a particular embodiment of our invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from our invention in its broader aspects; and we, therefore, intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

I. In a control for the control-valve mechanism of an electric circuit breaker, said mechanism comprising a movable control-valve member, an operating piston therefor, and an elongated rod interconnecting said tion in response to said venting operation by said valve member and said operating piston, opening-control valve.

a. means biasing said operating piston in a direction 5. In a control for the control valve mechanism of an to effect a circuit-breaker-closing operation of said electric circuit breaker, said mechanism comprising a valve member, movable control valve member, a first piston, and an b. latch means for restraining said operating piston in elongated rod interconnecting said valve member and a circuit-breaker-open position against said bias, id fi t i ton,

c. a closing-control operator for said latch means operable to release said latch means and thus render the latch means incapable of continuing to restrain said piston in its circuit-breaker-open position, thereby allowing said biasing means to operate said piston in a circuit-breaker-closing direction,

(1. an opening-control operator effective when operdead-center, e. and said spring means becomes effective to move said toggle linkage into substantially said reset posia. means biasing said first piston in a direction to effect a circuit-breaker-closing operation of said valve member,

b. an opening control operator comprising a second piston through which opening-control forces are developed,

c. a link for transmitting opening-control force from m F P olfenlngjcomml force said second piston to said first piston, and means dm'ing Peratmg through for coupling said first and second pistons to said N"? Comm link at spaced-apart points thereon,

forcetransmlttmg mefms effefmve when safld latch d. a pivot for said link located intermediate said means s reset, but IIICffCClZIV C when said latch spaced apan points, means not reset for transmlttmg openmg' e. latch means normally holding said pivot in a reset control force from said opening-control operator position to Said operating piston f. a closing-control operator for said latch means opf. and latch-resetting means for effectively resetting erable to cause Said latch means to release Said T latsh 3 t and m response to a pivot for motion, thereby allowing the bias on said seo 1 c means. if 1 of assist; arses: 3:152:34; 25123:; latch means is essentially completed the time the cirfrom its reset 508mm! breaker has reache.d clqsed p g. means for resetting said latch means and restoring 3. The control of claim 1 in which: b u

a. said opening-control operator comprises a second P pivot .Stanna y Sal reset. posmon. Immepiston through which opening control force is de- 2 2:3 2 follcwmg a releasing operation of sald latch ZTQTZ 12.233532225539232; 1'5 al l lfioii ife and means for "ligating a t of i i i; face of said second piston to develop said openingcomm Operator O.nowmg i rescuing 9 Sal control force latch means and said restoration of said pivot to said highpressure fluid remains in force substantially said reset POSlUOn, whereby openingdeveloping relationship with said one face of said control ,forces are ij p through lmk second piston while said circuit breaker is open, from sald t LP EF thereby opposing the bias on said operating piston 40 i comic 0 c aim m w m tending to produce circuit-breaker-closing opera- Sald openmgcomrol oPerator compnses an P tion of Said movable control valve member lng-control valve that is operable to cause highc. said opening-control valve, in response to a latch- Pressure fluid to act upon f face of and second releasing operation, is operable to vent the high- P to f p d penmg control force, pressure fluid acting on said one face of said secflu ld "f m 0nd piston, developing relatiopship with sa d one face of said d. said latch-resetting means is operable to reset said Second plston'whfle open latch means in response to a venting operation by Fhereby PP first f Said opening comrol valve of the high pl.essure mg to produce circuit-breaker-closlng operation of fluid acting on said one face of said second piston. movaple control valve m 4 The Conn-0| f claim 3 in which; c. said opening-control valve, in response to operaa. said force-transmitting means for transmitting {ion of Said latch mFans to release Pi P- opening-control force from said opening control erable vent i -P fluid actmg sfild operator to said operating piston comprises a link one face of 531d Second P' thfl'eby reducmg mounted on a pivot and operatively connected bethe force developed on Said Second Piston y Said tween said two pistons, fluid,

b. said latch means comprises a toggle linkage that is said latch-resetting means being Operable to reset main i d near i d dm i i whilg said latch means in response to a venting operation holding Said pivot in said reset position, 0 by said opening-control valve of the high pressure c. said closing-control operator releases said latch fl d t g d One afie f Said Second piston.

means by moving said toggle linkage out of its The mm] of Claim 6111 which: dead-center position, a, said latch means comprises a toggle linkage that is d. said resetting means comprises spring means biasmaintained near its dead-center position while ing said toggle toward said reset position near holding said pivot in said reset position,

b. said closing-control operator releases said latch means by moving said toggle linkage out of its dead-center position,

c said resetting means comprises spring means biasing said toggle toward said reset position near dead-center,

d. and said spring means becomes effective to move said toggle into said reset position in response to said venting operation by said opening-control valve.

8. The control of claim in which:

a. said opening-control operator comprises an opening-control valve that is operable to cause highpressure fluid to act upon one face of said second piston to develop said opening control force,

b said high-pressure fluid remains in forcedeveloping relationship with said one face of said second piston while said circuit breaker is open. thereby opposing the bias on said first piston tending to produce circuit-breaker-closing operation of said movable control valve member, and

c. said second piston is free to shift in response to movement of said link about said pivot in response to expansion or contraction of said elongated rod.

9. The control of claim 8 in which:

a. the high pressure fluid on said one face of said second piston drives said second piston in response to release of said pivot by said latch means,

b. a buffer is provided for stopping said second piston after a short travel thereof in response to release of said pivot. and

c. said link is free to continue moving under the influence of said first piston after said buffer stops said second piston.

l0. The control of claim 8 in which:

at said latch means comprises a toggle linkage that is maintained near its dead-center position while holding said pivot in said reset position.

b. said closing-control operator releases said latch means by moving said toggle linkage out of its dead-center position. 

1. In a control for the control-valve mechanism of an electric circuit breaker, said mechanism comprising a movable controlvalve member, an operating piston therefor, and an elongated rod interconnecting said valve member and said operating piston, a. means biasing said operating piston in a direction to effect a circuit-breaker-closing operation of said valve member, b. latch means for restraining said operating piston in a circuit-breaker-open position against said bias, c. a closing-control operator for said latch means operable to release said latch means and thus render the latch means incapable of continuing to restrain said piston in its circuitbreaker-open position, thereby allowing said biasing means to operate said piston in a circuit-breaker-closing direction, d. an opening-control operator effective when operated to develop an opening-control force for use in driving said operating piston through circuit-breaker-opening control motion, e. force-transmitting means effective when said latch means is reset, but ineffective when said latch means is not reset, for transmitting said opening-control force from said openingcontrol operator to said operating piston, f. and latch-resetting means for effectively resetting said latch means following and in response to a release of said latch means.
 2. The control of claim 1 in which resetting of said latch means is essentially completed by the time the circuit breaker has reached closed position.
 3. The control of claim 1 in which: a. said opening-control operator comprises a second piston through which opening control force is developed and an opening-control valve that is operable to cause high-pressure fluid to act upon one face of said second piston to develop said opening-control force, b. said high-pressure fluid remains in force-developing relationship with said one face of said second piston while said circuit breaker is open, thereby opposing the bias on said operating piston tending to produce circuit-breaker-closing operation of said movable control valve member, c. said opening-control valve, in response to a latch-releasing operation, is operable to vent the high-pressure fluid acting on said one face of said second piston, d. said latch-resetting means is operable to reset said latch means in response to a venting operation by said opening-control valve of the high-pressure fluid acting on said one face of said second piston.
 4. The control of claim 3 in which: a. said force-transmitting means for transmitting opening-control force from said opening control operator to said operating piston comprises a link mounted on a pivot and operatively connected between said two pistons, b. said latch means comprises a toggle linkage that is maintained near its dead-center position while holding said pivot in said reset position, c. said closing-control operator releases said latch means by moving said toggle linkage out of its dead-center position, d. said resetting means comprises spring means biasing said toggle toward said reset position near dead-center, e. and said spring means becomes effective to move said toggle linkage into substantially said reset position in response to said venting operation by said opening-control valve.
 5. In a control for the control valve mechanism of an electric circuit breaker, said mechanism comprising a movable control valve member, a First piston, and an elongated rod interconnecting said valve member and said first piston, a. means biasing said first piston in a direction to effect a circuit-breaker-closing operation of said valve member, b. an opening control operator comprising a second piston through which opening-control forces are developed, c. a link for transmitting opening-control force from said second piston to said first piston, and means for coupling said first and second pistons to said link at spaced-apart points thereon, d. a pivot for said link located intermediate said spaced-apart points, e. latch means normally holding said pivot in a reset position, f. a closing-control operator for said latch means operable to cause said latch means to release said pivot for motion, thereby allowing the bias on said first piston to drive said first piston in a circuit-breaker-closing direction and to displace said pivot from its reset position, g. means for resetting said latch means and restoring said pivot substantially to said reset position immediately following a releasing operation of said latch means, h. and means for initiating operation of said opening-control operator following said resetting of said latch means and said restoration of said pivot to substantially said reset position, whereby opening-control forces are transmitted through said link from said second to said first piston.
 6. The control of claim 5 in which: a. said opening-control operator comprises an opening-control valve that is operable to cause high-pressure fluid to act upon one face of said second piston to develop said opening control force, b. said high-pressure fluid remains in force-developing relationship with said one face of said second piston while said circuit breaker is open, thereby opposing the bias on said first piston tending to produce circuit-breaker-closing operation of said movable control valve member, c. said opening-control valve, in response to operation of said latch means to release said pivot, is operable to vent the high-pressure fluid acting on said one face of said second piston, thereby reducing the force developed on said second piston by said fluid, d. said latch-resetting means being operable to reset said latch means in response to a venting operation by said opening-control valve of the high pressure fluid acting on said one face of said second piston.
 7. The control of claim 6 in which: a. said latch means comprises a toggle linkage that is maintained near its dead-center position while holding said pivot in said reset position, b. said closing-control operator releases said latch means by moving said toggle linkage out of its dead-center position, c. said resetting means comprises spring means biasing said toggle toward said reset position near dead-center, d. and said spring means becomes effective to move said toggle into said reset position in response to said venting operation by said opening-control valve.
 8. The control of claim 5 in which: a. said opening-control operator comprises an opening-control valve that is operable to cause high-pressure fluid to act upon one face of said second piston to develop said opening control force, b. said high-pressure fluid remains in force-developing relationship with said one face of said second piston while said circuit breaker is open, thereby opposing the bias on said first piston tending to produce circuit-breaker-closing operation of said movable control valve member, and c. said second piston is free to shift in response to movement of said link about said pivot in response to expansion or contraction of said elongated rod.
 9. The control of claim 8 in which: a. the high pressure fluid on said one face of said second piston drives said second piston in response to release of said pivot by said latch means, b. a buffer is provided for stopping said second piston after a short travel thereof in response to release of saiD pivot, and c. said link is free to continue moving under the influence of said first piston after said buffer stops said second piston.
 10. The control of claim 8 in which: a. said latch means comprises a toggle linkage that is maintained near its dead-center position while holding said pivot in said reset position, b. said closing-control operator releases said latch means by moving said toggle linkage out of its dead-center position. 